PLANT-REGENERATION OF MESOPHYLL PROTOPLASTS FROM A CYTOPLASMIC ALBINO MUTANT OF LYCOPERSICON-ESCULENTUM CV LARGE RED CHERRY

Mesophyll protoplasts from in vitro grown plants of a cytoplasmic albino mutant of Lycopersicon esculentum cv. Large Red Cherry were isolated with yields between 0.4 to 4.4 × 106 protoplasts per gram leaf tissue. Success in the culture of these protoplasts was dependent on embedding of the protoplasts in 100 μ1 agarose droplets 0.6% (w/v). A plating efficiency of 4.0% was obtained when the protoplasts were cultured in TM-2 medium with sucrose concentrations of 8.7 to 9.6% (w/v) resulting in an osmotic pressure of 432 to 469 mOsmol kg-1. After 14 days of protoplast culture, microcalli with a diameter of 3 mm were observed. After 3 weeks, macrocalli were obtained which were transferred to regeneration medium. Regeneration of shoot primordia, with a frequency of 19%, was obtained on TM-4 medium supplemented with 1% (w/v) sucrose. The first shoot primordia were visible 10 weeks after protoplast plating. For development of the shoot primordia into shoots it was necessary to increase the sucrose concentration to 6% (w/v). Eight out of eleven regenerants were diploid (2 n = 2 x = 24); the other three were tetraploid. Efficient regeneration of mesophyll albino protoplasts from tomato opens the way to select at the cellular level for the chloroplast transfers. © 1990 Kluwer Academic Publishers.